It was a rare scene on Long Island: residents applauding a developer promising to transform their community from the ground up.

That's what happened at a public hearing last week on a plan to bring thousands of apartments and townhomes and tens of thousands of square feet of commercial construction to Riverside, a hamlet in Southampton Town that by some measures is Long Island's most economically...

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It was a rare scene on Long Island: residents applauding a developer promising to transform their community from the ground up.

That's what happened at a public hearing last week on a plan to bring thousands of apartments and townhomes and tens of thousands of square feet of commercial construction to Riverside, a hamlet in Southampton Town that by some measures is Long Island's most economically distressed community.

"We need this here," said Dawn Gilliam, whose daughter Kelly, 21, was killed in 2003 by a stray bullet fired outside a Riverside bar. "Yes, we're going to run into obstacles. . . . But we can make it work. You can't do nothing."

Plainview-based Renaissance Downtowns LLC, at the request of town officials, has crafted new zoning rules designed to attract developers to an area residents say struggles with abandoned homes, shuttered businesses and economic stagnation.

Renaissance's zoning envisions 2,267 housing units -- nearly triple the existing 788 units -- as well as 133,517 square feet of retail space and 62,000 square feet of professional and medical offices for the area, among other developments, according to an environmental study by Melville planning firm Nelson, Pope & Voorhis.

Many residents, who described drug sales and prostitution occurring in plain sight, said they were optimistic that new zoning could help Riverside leverage its location at the gateway of the North Fork and Hamptons and its position along the Peconic River.

"I look at this project as a rebirth," said Robert Brown, who has lived in Riverside about 20 years.

But some were put off by the level of development in the plan, which would allow buildings as tall as 4 1/2 stories in some areas. Christine Prete of nearby Flanders called the proposed density "unbelievable" and said the project is "starting to look like Queens."

Renaissance's form-based zoning would regulate everything from how buildings look to where they sit on their lots, but would allow a wider variety of uses, said Renaissance vice president Sean McLean, adding that the firm envisioned a "seaside" aesthetic.

Landowners would not have to adopt the new zoning but could opt in if they felt they could benefit from the new regulations, officials said.

The study noted a "potential for redevelopment to displace existing residents and businesses" and repeated a major obstacle cited by town officials: a pressing need for sewers in the area before any projects move forward.